For much of the 20th century, New York's "Freedom Tunnel" was an unused rail tunnel that housed a homeless community and the occasional graffiti tagger. Trains run through the tunnel nowadays, but metro-spelunkers still venture down into this underground cathedral.

Graffiti taggers, urban explorers, and photographers still brave the tunnel — oncoming trains, legality, and nerves be damned. Charles le Brigand, the creator of the video montage below, describes the tunnel as a ghostly, post-apocalyptic place:

It is a bizarre blend of dark and light, silence and rumble, solitude and multitude. As you penetrate the tunnel and walk along the tracks, the sunbeams perforating the ceiling and highlighting the railway gives the place a post-nuclear feel. Voices from children playing above in Riverside Park sound like lost souls and trains whistling and roaring through the ruins of the shanty towns send chills down your spine.

If they made a movie of Brian Wood's DMZ, this would be the place to film it.

Also, here are the first ten minutes of Marc Singer's Dark Days, a 2000 documentary about homeless people who lived in the Freedom Tunnel. Singer befriended the tunnel's residents and made the film to bring attention to their situation. Legendary turntable maestro DJ Shadow provided the soundtrack.